The present invention relates to surgical balloons, and more particularly to balloons suitable for introduction into a body cavity for containing a thermally conductive media used for ablation of cells within the cavity.
Surgical balloons have a variety of uses, including the containment of fluids used to necrose cells lining a body cavity. For example, it has now become common to treat excessive menstrual bleeding (menorrhagia) by inserting a balloon catheter into the uterus, filling the balloon with a thermally conductive media and heating or cooling the media to thermally kill the endometrial lining of the uterus. An exemplary thermal ablation process and apparatus utilizing a surgical balloon are described in U.S. Pat. No. 5,502,681 to Neuwirth et al.
As shown in U.S. Pat. No. 5,502,681, known surgical balloons are typically formed from latex, have a bulb shape, and inflate in a manner which enlarges the bulb shape uniformly to an approximately spherical or bulbous shape. In contrast, the uterine cavity is Y-shaped in cross-section. The material composition of known balloons is somewhat inelastic, preventing the balloons from readily conforming to the intra-uterine space. As a result, known bulbous surgical balloons do not inflate to contact the entire endometrial lining, in particular, in the area of the uterine cornua. This lack of contact may result in a portion of the endometrial lining escaping treatment.
It is therefore an object of the present invention to provide an improved surgical balloon that exhibits an increased contact area with a body cavity into which it is inserted when the balloon is inflated.
The problems and disadvantages associated with the conventional surgical balloons are overcome by the present invention which includes a surgical balloon for to insertion into a body cavity with a major chamber having a first volume and an annexed minor chamber communicating therewith and having a second volume less than the first volume. The balloon has a continuous outer wall which defines the exterior surface of the balloon on a first side and the interior hollow of the balloon on a second side. The wall is formed from a stretchable elastic material permitting the interior hollow of the balloon to accommodate a variable volume of fluid ranging from a minimum deflated volume associated with a relaxed state of the wall to a maximum inflated volume associated with a stretched state of the wall. The wall has a varying expansibility permitting a selected portion thereof to expand further in the stretched state than the remainder of the wall. The wall provides the balloon with an inflated shape within the cavity approximating the interior shape of the body cavity, including a first portion approximating the major chamber and a second portion approximating the minor chamber.